Dual‐Core and Quenching Resistance of Silicic Linkage‐Based Multiple Resonance Thermally Activated Delayed Fluorescence Emitters

Abstract Multiple resonance thermally activated delayed fluorescence (MR‐TADF) materials offer narrowband emission and efficiency but suffer from spectral broadening and aggregation‐caused quenching (ACQ) at high doped concentrations. In this study, two novel silicic linkage‐based dual‐core MR‐TADF emitters, DMeSiB and DPhSiB, are introduced, which effectively mitigate both concentration quenching and spectral broadening. DMeSiB and DPhSiB exhibit bluish‐green emission peaking at 493 and 495 nm with full‐width at half‐maximum (FWHM) values of 21 and 22 nm in toluene and high photoluminescence quantum yields exceeding 90% in doped films. At a doping concentration of 5 wt%, the organic light‐emitting diodes (OLEDs) based on DMeSiB and DPhSiB achieve maximum external quantum efficiencies (EQE max s) of 27.2% and 28.6% with narrow FWHMs of 25 and 24 nm, respectively. Over a doping concentration range of 5 wt% to 20 wt%, the OLEDs maintain high EQE max values of 23.5%, 21.4%, 19.2% and 24.9%, 22.7%, 19.3%, respectively. Even at a 20 wt% doping concentration, the FWHMs of the devices broaden by only 2 or 3 nm, reaching 27 nm. This structural design facilitates efficient luminescence while successfully suppressing spectral broadening and ACQ, leading to improved device performance.